A concerted global effort to tackle the causes of cancer linked to lifestyle, such as alcohol abuse, sugar consumption and obesity, has been urged on Monday by the World Health Organisation as it predicted that the number of new cases could soar by 70% to nearly 25 million a year over the next two decades.

Half of these cases are preventable, says the U.N.’s public health arm in its World Cancer Report, because they are linked to lifestyle. It is implausible to think we can treat our way out of the disease, say the authors, arguing that the focus must now be on preventing new cases.

Even the richest countries will struggle to cope with the spiralling costs of treatment and care for patients, and the lower income countries, where numbers are expected to be highest, are ill-equipped for the burden to come.

The incidence of cancer globally has increased from 12.7m new cases in 2008 to 14.1m in 2012, when there were 8.2m deaths. By 2032, it is expected to hit almost 25m a year – a 70% increase.

The biggest burden will be in low- and middle-income countries, where the population is increasing and living longer. They are hit by two types of cancers – first, those triggered by infections, such as cervical cancers, which are still very prevalent in poorer countries that do not have screening, let alone the HPV vaccine.

Second, there are increasingly cancers associated with the lifestyles of more affluent countries “with increasing use of tobacco, consumption of alcohol and highly processed foods and lack of physical activity”, writes Margaret Chan, director general of WHO, in an introduction to the report.

Dr Christopher Wild, director of the International Agency for Research on Cancer (IARC) and joint author of the report, said when people know his job, they asked whether a cure for cancer had been found, yet few think about preventing the disease in the first place.

“Despite exciting advances, the report shows that we cannot treat our way out of the cancer problem. More commitment to prevention and early detection is desperately needed in order to complement improved treatments and address the alarming rise in the cancer burden globally.”

His co-author, Dr Bernard Stewart from the University of New South Wales, talked of “the crucial role of prevention in combatting the tidal wave of cancer” and called for discussion on how to encourage people to change their lifestyles, including a tax on sugared drinks, which could be one possible brake on cancers caused by obesity and lack of physical exercise.

The world had moved on from what Stewart called a “naive approach” to smoking, which causes lung and other cancers, and once was limited to handing out leaflets and haranguing people to give up. He cited the global tobacco control treaty from the WHO, which incentivises governments to pass laws banning smoking in public places.

The World Cancer Report, an 800-page volume on the state of cancer knowledge, which is the first for five years, must open up the debate, said Stewart.

“In relation to alcohol, for instance, we are all aware of the effects of being intoxicated but there is a burden of disease not talked about because it is not recognised,” he said.

The report shows that alcohol-attributable cancers were responsible for a total of 337,400 deaths worldwide in 2010, mostly among men.

The majority were liver cancer deaths, but drinking alcohol is also a risk for cancers of the mouth, oesophagus, bowel, stomach, pancreas, breast and others.

“Labelling and availability and the price of alcohol should all be on the agenda,” said Stewart.
So should taxation of sugar-sweetened drinks, he said. The report calls for efforts to reduce the amount of cola, lemonade and other drinks containing substantial amounts of added sugar to become a high priority. Obesity, said Stewart, was a greater risk for diabetes than cancer, but cancer awareness was so great in our communities that the cancer risk was likely to put more pressure on politicians to act.

Lung cancer is the most commonly diagnosed form of the disease among men (16.7% of cases) and the biggest killer (23.6% of deaths), says the IARC report. Breast cancer is the most common diagnosis in women (25.2%) and caused 14.7% of deaths, which is a drop and now only just exceeds lung cancer deaths in women (13.8%). Bowel, prostate and stomach cancer are the other most common diagnoses.

Some of the causes of the rise in breast cancer are not amenable to change – women choosing to have fewer children and to have them later in life increase their risk. But increased breast feeding is protective. “There are some things we can change,” said Wild. “There is increasing evidence for the role of alcohol consumption in breast cancer and some evidence for obesity, particularly in post-menopausal women.”

In low- and middle-income countries, cancer rates could be brought down by relatively simple interventions. About 80% of cervical cancer deaths are in the developing world, but now there is a vaccine against human papillomavirus (HPV) which causes most cases and is routinely given to UK schoolgirls. Cheap and simple screening techniques could detect cases early, when they are treatable.

There are also vaccines against hepatitis B, which could prevent many liver cancers. Infections are responsible for about 16% of all cancers.

Wild said the next most urgent goal – after stopping the further spread of the smoking habit – was to find ways to diagnose breast cancer early in poor countries where mammography equipment and people trained to operate the machines and interpret the X-rays were not affordable.

The least developed regions will bear the brunt of the cancer increase in the coming years. More than 60% of cases and 70% of deaths occur in Africa, Asia and Central and South America.

Cancer Research UK said the predicted steep rise in cancers was shocking and so was the fact that half were preventable. It called on governments to take action, such as banning “glitzy packs” of cigarettes that attract children.

Jean King, Cancer Research UK’s director of tobacco control, said: “People can cut their risk of cancer by making healthy lifestyle choices, but it’s important to remember that the government and society are also responsible for creating an environment that supports healthy lifestyles. It’s clear that if we don’t act now to curb the number of people getting cancer, we will be at the heart of a global crisis in cancer care within the next two decades.”